See exactly when rain will start and stop with a minute-by-minute precipitation nowcast for the next hour.
23°
Humid and Mostly Cloudy
Feels Like: 23°
Min: 23°
Max: 30°
The next few hours will be humid and mostly cloudy, with today reaching 30°C and dropping to 23°C. The coming days will be drizzle
Compare today's weather with yesterday's data and track temperature trends over time.
Hourly Forecast
Daylight Hours
05:28
Sunrise
17:28
Sunset
Moon
Waxing Gibbous
13:38
Moonrise
01:30
Moonset
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View stargazing scoreWeather in San Francisco today, September 21, 2026
San Francisco starts September 21, 2026 looking damp, with rain in the forecast and wetter spells likely at times. Waterproof kit is the safer call for early plans. Expect a grey start, with morning cloud around 81% by 11:00. Outdoor plans early on should not rely on bright skies.
Temperatures climb from an overnight low near 23°C toward a daytime high of about 30°C. Relative humidity sits between 67% and 100%, reaching its peak around 23:00. A lighter breeze peaks around 11:00 near 2.3 km/h.
The second half of the day still looks unsettled, with rain probability around 100% by 15:00. Dense cloud near 100% at 20:00 keeps the feel grey. Visibility stays generally good near 10.6 km on average, though it can drop toward 0.4 km in thicker cloud or showers. The sun rises at 05:28 and sets at 17:28, for a total of 11 hours 59 minutes of sunlight today.
Overall, San Francisco on September 21, 2026 suits indoor plans or waterproof kit, especially while rain chances stay near 100% and the high sits around 30°C.
Frequently asked questions about weather in San Francisco
How warm does it get in San Francisco?
The warmest month in San Francisco is August, with average high temperatures of 33°C. The average temperature during this period is around 28°C.
How cold does it get in San Francisco?
The coldest month in San Francisco is February, with average low temperatures of 24°C. The average temperature during this period is around 27°C.
What is the wettest time of year in San Francisco?
The wettest month in San Francisco is December, with an average of 301mm of precipitation.
What is the driest time of year in San Francisco?
The driest month in San Francisco is April, with an average of 133mm of precipitation.
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